On November 22, 1963, JFK was riding through Dallas in a motorcade alongside First Lady Jacqueline Kennedy (later Onassis), Texas Governor John Connally, and Connally's wife, Nellie. As the four worked their way through Dealey Plaza, former U.S. Marine Lee Harvey Oswald fired three shots — one of which hit Governor Connally, and two that struck and killed President Kennedy. A spectator waiting to see the president ride by also got wounded in the shooting.

Police arrested Oswald shortly after the shooting, but two days after the assassination, a man named Jack Ruby shot and killed him as police were transferring Oswald to county jail.

A 10-month investigation by the President's Commission on the Assassination of President John F. Kennedy, known as the Warren Commission, concluded that Oswald was the sole shooter. Despite the official findings, and video that was later released showing the moment JFK was killed, conspiracy theories about what actually happened that day persist. Some hope the documents set for release will either give credence or squash them for good. In the meantime, here are the top three theories regarding JFK's assassination.

The Grassy Knoll

By far the most popular theory, the idea that a second shooter on a grassy knoll was involved in killing the president sprang not from conspiracy theorists but from the government itself. According to The Washington Post, the Warren Commission concluded that Lee Harvey Oswald did shoot the president, but added there was “probably” a conspiracy involving another shooter. The Post reports that conclusion has since been discredited, but the doubt that Oswald acted alone lingered.

Kennedy's death was a result of Russian or Cuban planning.

In 1961, Kennedy authorized an operation known as the Bay of Pigs, an effort to dismantle Fidel Castro's administration in Cuba. In 1962, the Cuban Missile Crisis — a confrontation between the U.S. and the Soviet Union in which the Soviet deployed a ballistic missile in Cuba in response to U.S. missile deployment elsewhere — marked the closest the U.S. ever came to the Cold War actually breaking out into battle. Some theorized that Kennedy's death was a result of the U.S.'s fight against communism, particularly given that Oswald had moved to the Soviet Union for a time.

Others think the CIA was behind his death.

Some have posited that the CIA was actually behind Kennedy's assassination. According to CNN, some believe someone associated with the CIA actually fired the shot that killed the president, while others believe the CIA knew there would be an attempt on Kennedy's life and did nothing to stop it. Politico reported that according to a report written in 2013 by the CIA's top historian, the question has been raised within the agency whether the CIA's then-director, John McCone, was complicit in withholding crucial information on the assassination from investigators.